Method and apparatus for the manufacture of x-ray grids and kindred devices



2,288,972 0F X-RAY y 1942- R. MILLENAAR METHOD AND APPARATUS FOR THE MANUFACTURE GRIDS AND KINDRED DEVICES Filed Feb. s, 1958 3 Sheets-Sheet 1 INVENTOR. file/Mk0 lV/ltE/VAAAE ATTORNEYS.

July 7, 1942. R. MILLENAAR METHOD AND APPARATUS FOR THE MANUFACTURE OF X GRIDS AND KINDRED DEVICES Filed Feb. 8, 1938 R. s WM w mm m Q w ww W m Q\ A m o A m N N 8NN1 x llllllll |llll|| II\ s sheds-sheet a INVENTOR. M; LEMMR CTURE QF X-RAY EVICES 4 III R. MILLENAAR RATUS FOR THE MANUFA GRIDS AND KINDRED D Filed Feb. 8, 1938 [/77/ lU/Ifi/I METHOD AND APPA July 7, 1942.

R Q\ Q i 4 .v Q Q a m 0 .22? ESQ N 2 Q w MN MN Q. v m w .1 a H m m \a .i v vn w Q N ,Q sv Oafi MP 9 .b B wm M 8N 'I ORNEm Patented July 7, 1942 UNiTED STATES PATENT OFFICE METHOD AND APPARATUS FOR THE MANU- FACTURE F X-RAY GRIDS AND KINDRED DEVICES Richard Millenaar, Oak Park, Ill., assignor to The Richardson Company, Lockland, Ohio, at corporation of Ohio Application February 8, 1938, Serial No. 189,422

17 Claims.

I shall describe my invention in connection with the manufacture of what are known as X- ray grids, it being understood that the method and apparatus herein set forth are applicable to the manufacture of other articles presenting the same or similar problems.

In the taking of X-ray photographs, as is well known, an X-ray tube is located upon one side of the body to be photographed and the sensitized photographic film is located upon the other. cut into layers, the relatively soft foil occurring The rays sent out by the X-ray tube travel as between other laminae is mashed and distorted, from a point source, and give on the photoand peened over the edges of adjacent laminae so graphic plate what may be termed a shadow as to give a structure in which the grid form is image. While X-ray photographs have been interrupted and non-uniform. Attempts to make made in this way with satisfaction for a large X-ray grids in this fashion have, therefore, uninumber of years, yet there is some apparent formly failed. diffusion and deflection of the rays; and it has In the practice of my invention I produce X- been ascertained that the clarity of the shadow ray grids or like articles by the rapid machine image will be very greatly improved (so much production and assembly of individual laminae, so that in many instances details can be deterwhich are positioned between protective covermined upon the film which otherwise would not ing sheets in ways which I shall hereinafter set be apparent) if there is interposed between the forth. The fundamental problems are the mao-bject and the film a grid structure consisting chine production of cleanly and accurately cut uniformly of alternate layers of material opaque laminae without separation or displacement of to X-rays and material transparent to X-rays. the lead foil, mashing of the lead foil, or ac- The rays are caused to impinge upon the grid cumulation of lead dust or splinters between the in a direction very nearly parallel to the plane laminae and the cover sheets; the rapid machine of the said layers therein. X-ray grids have assembly of laminae on edge, between cover heretofore been manufactured of alternate thin sheets without displacement thereof from the laminations of lead foil or the like, and lamina- 3O desired position; and the binding of the whole tions of paper, the said laminations, on edge, betogether into a substantially solid mass. ing interposed between cover sheets of Celluloid The several objects of my invention I accomor similar composition. Such grids, usually of plish by that method and in that structure and foreign manufacture, have so far as is known arrangement of parts of which I shall now set been assembled by hand in a very laborious fashforth a particular exemplary embodiment. Refion, and are very costly. erence is'now made to the drawings wherein:

The fundamental object of my invention is Fi ure l'is an elevational view of my machine. the provision of a means and method for the Fig. 2 is, a sectional view thereof, taken along manufacture of X-ray grids or of similar prodthe lines 22 of Fig. 1. ucts which are inexpensive and rapid while giv- 40 Fig. 3 is a view of one of the locking members. ing accurate and satisfactory results. The Fig. 4 is a'plan view of the machine. problem, in a sense, is one of the machine ma'n'u- Fig. 5 is a longitudinal sectional view taken facture of structures of this classj and a'ncilalong the center line of Fig.4. lary objects of my invention will be apparent in Fig. 6 is an enlarged side elevation of an the ensuing discussion where the various 'prob- Kelby g produced 011 y ach n lems are set forth. In my machine I provide an upper and a lower By way of example, it is possible to assemble platen. Interspaced cover sheets are positioned laminae of lead foil and the like, and laminae 'withrespect to these platens so that laminae of paper or other fabric, saturated in an incommay be assembled therebetween; and between pletely cured synthetic resin (e. g. a resin varthe sheets there rides a compression member.

nish consisting of the incompletely polymerized resin dissolved in a solvent such as water or alcohol). Before assembling, the saturated laminae are dried. In this way a block can be built up in which the layers are accurately formed For the laminae, I first make composite sheets by taking one or two layers of paper or the like, saturated in synthetic resin, a layer of lead foil and one or two additional layers of saturated stock, the lead foil being sandwiched between the other layers. This composite sheet is pressed and cured in the ordinary way for laminated resinous products. The laminae for the X-ray grid are formed by a die-cutting operation of such nature that the die simultaneously cuts both longitudinal edges of the laminations. The laminations cut in this way are pushed through the die in side by side relationship and on edge, whereby'they are accurately assembled together in the desired relationship and are pushed, against the resistance of the restraining or compression member, between the two cover sheets. By continued operations of the machine and the feeding to it of composite sheets, as hereinabove explained, the body of assembled laminae between the two cover sheets is produced. There is no essential limitation upon the length of X-ray grids which may be made in this way, nor is there any limitation on the width of the grid other than the maximum width for which the machine is constructed. The two cover sheets are previously coated with a thermoplastic cement which is hard at normal temperatures, but which, when the lower platen (and preferably the upper platen also) are heated, as with steam or the like, will fuse and bind the composite structure together. By the die-cutting operation to which I have referred, spalling and peening of the lead foil layer is prevented; and I keep my dies clean by means of air or other fluid, so that shavings or other pieces of the lead foil will not be incorporated in the grid structure.

Before proceeding to a description of the machine for this purpose, I will first describe an exemplary grid as illustrated in Fig. 6. This grid comprises interspaced cover sheets 4 and 5. Between the sheets there are laminations indicated generally at 5. Each lamination comprises a layer of lead or the like 1 sandwiched between layers 3 and 9 of material transparent to X-rays. In an exemplary embodiment, the over-all thickness of the article may be from .120 to .125 inch, whereas the space between the two cover sheets 4 and 5 may be one-sixteenth of an inch. The total thickness of each lamination may be .020 inch. Each lamination may contain a layer of lead .001 inch in thickness, the remainder of the thickness of the lamination being paper saturated in resin. With the dimensions just given, there will be fifty punchings or laminations per linear inch of the product. It will be understood that the dimensions which I have given are for the sake of a complete exemplary disclosure and do not constitute limitations, since these may be varied as desired. I have hereinabove discussed the matter of limitations as to size. With my particular machine I am currently making X-ray grids 17 inches by 20 inches; but larger or smaller ones can readily be made in accordance with my teachings.

In producing the stock for the lamlnations I ordinarily take two sheets of paper which has been saturated in a resin, as hereinabove set forth. Any of the synthetic resins may be used. Ordinarily I use a phenol formaldehyde resin of the Bakelite type. On these two layers I lay a layer of lead foil, and over this assemble two more layers of the saturated paper. The whole is placed between the usual polished plates in a press and the laminated structure is cured under heat and pressure, as is usual in synthetic resin practice. I do not desire, however, to be limited to laminae containing synthetic resin, since it will be perfectly apparent as the description pro ceeds that there are many ways of making the composite sheet for the laminations, and that material which is opaque to X-rays and material transparent to X-rays may be adhered together in a wide variety of ways for the uses of this invention.

The general details of the machine will best be appreciated from Fig. l, where on a base IE] I mount a reciprocating ram ll bearing a die member 52. This ram may be caused to move in suitable ways, as by an eccentric indicated at l3, having a drive indicated generally at 14. The details of this construction are illustrated, but do not form a limitation upon my invention; and various ways of actuating the ram or the die may be adopted in accordance with the skill and desire of theworker in the art. The machine has cooperating die members indicated generally at !5 and H5, forming together a female die part, the member I2 being a male die part, The die members l5 and [6 are suitably supported in the machine. On a level with the upper surface of the die member It, the machine has a fixed platen member ll. A movable platen member [8 is hinged as shown at l9, and may be brought down over the fixed platen with a slight interspacing therebetween. The fixed platen may be perforated as at 20 and may have means 2| for the introduction therein of a heating medium, such as steam. While I have not shown the upper platen as heated, and while I have not found it necessary to heat it, yet it will be within the skill of the worker in the art to provide perforations in this platen also, together with flexible connections for the admission of heating fluid. It is well, also, to provide means for cooling the platens after the completion of the formation of the article; and the same or different fluid connections may be employed with suitable valves for the admission of a cooling fluid, such as water. Between the platens there is a compression member 22 which is urged toward the die by a weight 23, through the intermediary of a cable 24 which may be passed over sheaves 25 and 26. I preferably provide a weight 23 on each side of the machine.

The construction of the cooperating parts of the machine will be best understood from Fig. 5, where like parts have been given like'index numerals. In this figure the female die members l5 andlfi are shown aflixed to blocks 2'! and 28, extending across the machine between head members la. The blocks 21 and 28 are interspaced as at 29 by approximately the width of the laminae or punchings. The cover sheets 4 and 5 are shown lying respectively against the platen members [8 and I1, and the compression member 22 is shown lying between the cover sheets. The blocks 21 and 28 have curved noses 30 and 3|, and the forward ends of the cover sheets 4 and 5 are shown as following the curvature of these noses and being interspaced thereby. The cover sheets are firmly held in position against these noses by locking members 32 and 33. One of these members is shown in detail in Fig. 3. It has a curved edge following generally the contour of the nose, and is slidably mounted in ways in the heads I a on pins 34. The ways are indicated in dotted lines at 35. A bolt 36, rotatably mounted in the locking member at each end, may be threaded into a threaded perforation in the heads la; and the bolts in question may be caused to draw the locking members tight. Fig. 2 may also be referred to for a better understanding of the relationship of these parts. By the locking means aforesaid, the ends of the cover sheets 4 and are firmly held so that these sheets cannot move with the laminations to the left.

I provide vertically extending guide means indicated at 31, for the lamination sheet 6. These guide means serve to carry the lamination sheet downwardly past the female die members l5, l6. Ordinarily I rely on gravity for this; but it does not constitute a departure from the spirit of my invention to provide positive feeding means for the lamination sheet 6, if desired, such as pinch rolls or the like. Below the level of the top surface of the die member 16 I provide a stop 38. It will be noticed that the action of this stop is-such as to cause the lamination sheet to cover completely the opening of the female die I5, Hi. When the male die I2 is actuated, therefore, it forms a punching by cutting both longitudinal edges thereof. The punching thus formed is forced into the space between the two members and I6; and at each stroke of the male die a portion of the material is lost. I have found that by forming my laminae of punchings which are simultaneously cut on both longitudinal edges, I obviate the difficulties hitherto encountered with spalling or speening of the lead foil, or separaiion of layers and the like. The loss of the waste material is relatively unimportant. In order to keep the dies clean, I provide fluid means 39 through which a continuous or intermittent blast of air is caused to blow from the die surfaces any splinters or fragments of material adhering thereto. By the successive operation of the male die l2 and the continuous feeding of the lamination sheet 6, a succession of laminae builds up in the space between the blocks 21 and 28 in the desired order, and correctly assembled on edge. As the assembly grows it passes out between the noses 30 and 3| of the blocks and enters the space between the cover sheets 4 and 5, displacing the compression member 22. The operation which I have just described is continued until the desired space between the cover sheets 4 and 5 is filled up with the correctly assembled laminae, the laminae moving progressively to the left. The actual space between the cutting edges of the die members I5 and IE is slightly less than the space between these members elsewhere and between the blocks 21 and 28. This is to say that beyond their cutting edges the members 15 and I5 and the blocks referred to are slightly relieved. As is well known, a punching is laterally compressed as it passes through the die and slightly expands thereafter. The space between the dies !5 and I6 between the block is such as to keep the laminae in assembled relationship; but the laminae cannot pass to the right and come out through the female die construction, for reasons which are now apparent.

Previous to placing the cover sheets 4 5 in my machine I have coated the surfaces thereof with a thermoplastic cement. I am not limited to any particular material for the cover sheets, and may use any desired fabric web or sheet includin but without limitation, Celluloid or any molded clear plastic. However. I have been using in practice cover sheets made up of a series of laminations of paper saturated in incomplete- 1y polymerized resin, for example. Bakelite, or one of the urea resins. and pressed and cured in the usual way. The thermoplastic cement which I have been employing is a so-called Bakelite cement or other similar product available the market and believed to consist largely of a rubber resin dissolved in a suitable volatile organic solvent. Such a cement dries hard, but

retains, for very long periods .at least, its thermoplasticity and can be softened by heat. The nature of the thermoplastic cement is, however, not a limitation on my invention.

During the operations aforesaid, the upper platen I8 is in the lowered position as shown in Fig. 5. This platen may be held down by its own weight and the bolts illustrated at 45 used to interspace it from the lower platen; or the bolts or other suitable means may be employed to clamp the upper platen to the lower platen. At the conclusion of the operations aforesaid and when the desired assembly of laminations has been made between the cover sheets 4 and 5, I apply heat to one or both of the platens so as to fuse the thermoplastic material and bind the whole structure. into one integral mass. The compression member 22 serves to keep the laminae in proper assembled relationship. I have found it advisable, however, during the pressing and curing stage to wedge the compression member 22 to the right by inserting wedges between it and the standard 4| which supports the outer end of the fixed platen I1 and the ears 22a of the compression member. Also during the curing stage I prefer tobring the die l2 to rest in its forward position, i. e. in the position in which it lies between the members 15 and 15, in order to prevent any possibility of displacement of the laminae in this direction.

When the grid structure has been built up in the way described, and is cooled and solid, the edges are trimmed as may be desired. The whole may be placed in a suitable frame, or may be given a metal binding.

Modifications may be made in my invention without departing from the spirit of it.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A mechanism for the manufacture of X-ray grids or similar articles comprising upper and lower platens, means for anchoring cover sheets so that said sheets respectively lie against said platens with a space between, and punch means for cutting laminations and for directing said laminations on edge in assembled relationship between said cover sheets, and moving them on edge between the said stationary cover sheets as said assembly grows.

2. A mechanism for the manufacture of X-ray grids or similar articles comprising upper and lower platens, means for anchoring cover sheets so that said sheets respectively lie against said platens with a space between, and punch means for cutting laminations and for directing said laminations on edge in assembled relationship between said cover sheets and moving them on edge between the said stationary cover sheets as said assembly grows, and means for heating at least one of said platens whereby the ccmposite article may be bound together by adhesive of thermoplastic character previously placed upon said cover sheets.

3. In a machine of the character described, a frame, a hollow die in said frame, a platen connected with said frame at the level of the hollow in said die, means in connection with said platen and said die for anchoring a cover sheet, a punch operable in connection with said die to form punchings and to cause said punchings to pass through said die in assembled relationship and to be led against said cover sheet, and means for operating said punch means. '7

4. In a machine of the character described, a

frame, a die in said frame consisting of spaced female members, mounting means for said die members, a male die, means for reciprocating said male die, means for feeding material in front of said male die, and stop means for causing said material at each feeding motion to be fed beyond the opening between said female die members, whereby during the punching operation a punching is made by simultaneously shearing both sides thereof.

5. In a machine of the character described, a frame, a die in said frame consisting of spaced female members, mounting mean for said die members, a male die, means for reciprocating said male die, means for feeding material in front of said male die, stop means for causing said material at each feeding motion to be fed beyond the opening between said female die members, whereby during the punching operation a punching is made by simultaneously shearing both sides thereof, and fluid pressure means for keeping said die members clean during repeated punching operations.

6. In a mechanism of the character described, a male die for cutting laminations and moving them in a direction transverse to their planes, means for reciprocating said die, spaced female die members, blocks for supporting said members leaving a passageway between, a platen at the level of one of said die members, a curved nose on the block supporting said die member along the surface of which a cover sheet may be placed, and means for locking said cover sheet to said nose, whereby a series of punchings produced by said die means, may be caused to pass through said passageway in assembled relationship and to lie against said cover sheet on said platen.

7. In a mechanism of the character described, a male die for cutting laminations and moving them in a direction transverse to their planes, means for reciprocating said die, spaced female die members, blocks for supporting said members leaving a passageway between, a platen at the level of one of said die members, a curved nose on the block supporting said die member along the surface of which a cover sheet may be placed, means for locking said cover sheet to said nose, whereby a series of laminations produced by said die means, may be caused to pass through said passageway in assembled relationship and to lie against said cover sheet on said platen, a second platen adapted to be spaced from the first, a nose on the second block and locking means for fastening a cover sheet thereto as hereinabove set forth, and means between said platens and lying between said cover sheets for exerting pressure on said assembly of laminations against its direction of movement.

8. In a machine 'of the character described, a frame, a ram reciprocable in said frame, a male die on said ram for cutting laminations and moving them in a direction transverse to their planes, stationary blocks in said frame, spaced female die members having a passageway therebetween, means for anchoring cover sheets to said blocks, spaced platen means lying on the outer side of said cover sheets and means for feeding material to be sheared to said dies, whereby a series of laminations is made by punching, passing progressively through said passageway and being positioned between said cover sheets.

9. In a machine of the character described, a frame, a ram reciprocable in said frame, a male die on said ram for cutting laminations and moving them in a direction transverse to their planes, stationary blocks in said frame, spaced female die members having a passageway therebetween, means for anchoring cover sheets to said blocks, spaced platen means lying on the outer side of said cover sheets and means for feeding material to be sheared to said dies, whereby a series of laminations is made by punching, passing progressively through said passageway and being positioned between said cover sheets, said means for feeding comprising guideways for said material to be punched, said die means being adapted to punch said sheet material across the width thereof, and stop means adapted to cause said feeding means to feed material over and beyond the space between said femaledie members, whereby said punchings are made by the simultaneous shearing of both edges thereof.

10. In a machine of the character described, a frame, a ram reciprocable in said frame, a male die on said ram for cutting laminations and moving them in a direction transverse to their planes, stationary blocks in said frame, spaced female die members having a passageway therebetween, means for anchoring cover sheets to said blocks, spaced platen means lying on the outer side of said cover sheets and means for feeding material to be sheared to said dies, whereby a series of laminations is made by punching, passing progressively through said passageway and being positioned between said cover sheets, said means for feeding comprising guideways for said material to be punched, said die means being adapted to punch said sheet material across the width thereof, and stop means adapted to cause said feeding means to feed material over and beyond the space between said female die members, whereby said laminations are made by the simultaneous shearing of both edges thereof, and fluid pressure means for keeping said dies clean.

11. In a machine of the character described, a frame, a ram reciprocable in said frame, a male die on said ram for cutting laminations and moving them in a direction transverse to their planes, stationary blocks in said frame, spaced female die members having a passageway therebetween, means for anchoring cover sheets to said blocks, spaced platen means lying on the outer side of said cover sheets and means for feeding material to be sheared to said dies, whereby a series of laminations is made by punching, passing progressively through said passageway and being positioned between said cover sheets, said means for feeding comprising guideways for sheet material to be punched, said die means being adapted to punch said sheet material across the width thereof, and stop means adapted to cause said feeding means to feed material over and beyond the space between said female die members, whereby said laminations are made by the simultaneous shearing of both edges thereof, and compression means for restraining an assembly of laminations in the direction of their motion.

12. A process of making an X-ray grid which comprises joining a layer of X-ray impermeable material to at least one lamina of X-ray permeable material so as to produce a stiff, selfsustaining composite, capable of being punched into laminations, forming a series of punchings from said composite between female die members forming a throat, by the action of a male die member whereby said punchings are out singly and are moved through said throat in a growing assembly with the planes of the punchings transverse to their direction of motion in said throat, and as said assembly grows restraining the movement thereof so as to compress said assembly in the direction of its motion.

13. A process of claim 12 in which the X-ray permeable lamina of said composite material for punching is a sheet material saturated in a synthetic resin and pressed and cured in combination with said X-ray impermeable layer whereby to form a stiff composite, V

14. The process of claim 12 in which prior to each punching operation said composite is passed across and beyond said female dies so that both edges of each punching are sheared in the same punching operation.

15. The process of claim 12 in which prior to each punching operation said composite is passed A lamina of fibrous material treated with a synthetic resin and pressed and cured against said metal foil. 7

16. The process claimed in claim 12 involving the movement of said assembly between X-ray permeable cover sheets which are stationary during said movement, until a sufficient portion of said assembly has been moved between said cover sheets to form an X-ray grid, and involving the subsequent adhesion of said cover sheets to said assembly positioned therebetween.

17. The process claimed in claim 12 involving the movement of said assembly between X-ray permeable cover sheets which are stationary during said movement, until a sufficient portion of said assembly ha been moved between said cover sheets to form an X-ray grid, and involving the subsequent adhesion of said cover sheets to said assembly positioned therebetween, said stationary cover sheets being coated with a non-tacky thermo-plastic adhesive during the movement of said assembly and said adhesion being accomplished by heat.

RICHARD MILLENAAR. 

